Precious metal plating barrel



Oct. 16, 1962 E. o. NEILSON PRECIOUS METAL PLATING BARREL 2 Sheets-Sheet 1 Filed April 24, l

Oct. 16, 1962 o, NElLSON 3,058,902

PRECIOUS METAL PLATING BARREL Filed April 24 1961 2 Sheets-Sheet 2 INV EN TOR.

3,058,902 PRECIOUS METAL PLATING BARREL Elmer 0. Neilson, North Lake, 111., assignor to Mercil Plating Equipment Company, Chicago, 111., a corporation of Illinois Filed Apr. 24, 1961, Ser. No. 105,063 Claims. (Cl. 204-213) This invention relates generally to electroplating apparatus and especially to apparatus for bulk electroplating from precious metal solutions.

The demand for electroplated coatings of precious metals has been extended from jewelry to precision screw machine products and electronic components. A concomitant interest has developed in miniature plating barrels that can be used in electroplating small, precision parts in bulk with minimal employ of the precious metal solutions. However, difficulties have been encountered in using electroplating barrels of conventional design. The small, delicate parts are frequently distorted or damaged in processing; and adequate electrical contact with the parts has been diflicult to maintain. Reduced barrel speeds have been required to minimize these problems. Low and costly production rates have resulted.

An important object of the present invention is, therefore, to provide apparatus that is highly adapted to the bulk electroplating of small, delicate parts.

Another object of the invention is to provide electroplating apparatus that avoids abuse of the charged parts.

Yet another object of the invention is to provide a new and improved contact for electroplating barrels.

And yet another object of the invention is to provide a contact for electroplating barrels that is easily removed for cleaning.

A further object of the invention is to provide an electroplating barrel that can be operated at normal speeds with safety to a charge of small, delicate parts.

A still further object of the invention is to provide an electroplating barrel from which parts are easily discharged.

And a still further object of the invention is to provide an electroplating barrel structure that prevents lodging of mechanically aggregated parts.

Additional objects and features of the invention pertain to the particular structure and arrangements whereby the above objects are attained.

A structure in accord with the invention includes a pair of barrel heads arranged to be rotated in spaced relationship, one of the heads being electrically insulative and having an electrically conductive element therein; ribs fixed between the heads at arcuately spaced locations; perforated panels between adjacent ribs; and a massive contact rod fixed to each of the ribs internally of the perforated panels, each of the contact rods being electrically connected to the conductive element in the one head, the rods exposing a substantial area to the parts charged into the barrel.

The invention, both to its structure and mode of operation, will be better understood by reference to the following disclosure and drawings forming a part thereof, wherein:

FIG. 1 is a perspective view of an electroplating barrel constructed in accordance with the invention;

FIG. 2 is an enlarged, end elevational view in crosssection of the electroplating barrel of FIG. 1;

FIG. 3 is an enlarged, cross-sectional view of a contact-mounting rib for use adjacent the removable panel of the electroplating barrel of the invention;

FIG. 4 is a view similar to the showing of FIG. 3 but illustrating an intermediate rib;

rates Patent the FIG. 5 is an enlarged view taken along the line 5-5 of FIG. 2;

FIG. 6 is a perspective view of a contact member for use on an intermediate rib;

FIG. 7 is a perspective view of a contact member for use on a rib adjacent the removable panel;

FIG. 8 is an end elevational view in cross-section showing schematically the accumulation of parts on one of the ribs adjacent the removable panel; and

FIG. 9 is a showing similar to FIG. 8 but illustrating discharge of the accumulated parts.

Referring now in detail to the drawings, specifically to FIGS. 1 and 2, a miniature electroplating barrel apparatus of the portable type is indicated generally by the numeral 20. The barrel apparatus 20 will be seen to include a live end flange assembly or barrel head 22 and a drive end flange assembly or barrel head 24, the heads 22 and 24 being spaced apart and rotatably mounted respectively to upright standards 26 and 23'. At their lower extremities, the standards 26 and 28 are advantageously fashioned to terminate in feet 30 in order that the barrel apparatus 20 can be free-standing when placed on a generally horizontal surface. Hanger brackets 32, each comprising a horizontal arm 34 having hook members 36 at each end, are affiXed to the standards 26 and 28 in a location generally vertically above the heads 22 and 24-. The hook members 36 extend laterally beyond the standards 26 and 28 for supporting the barrel apparatus 20 in an electroplating tank.

The heads 22 and 24 are joined by interconnecting ribs, in particular, a pair of ribs 38 adjacent a removable panel 40 and a sufficient number of intermediate ribs 42 to provide a strong barrel framework. The lateral space between the ribs 38 is closed oif by a removable panel 40 which is fashioned with tapered lateral edges these lateral edges cooperatively seat against the ribs 38. The panel 40 is also provided with a handle 44- and a clamp element 46.

The other lateral spaces between the several ribs are closed oil with panels 48; and as will be noted with reference to FIG. 2, the ribs 38 and 42 are provided with elongated, longitudinal slots or grooves 5% flaring outwardly from the sides of the rib to receive the edges of the panels 48. The panels 40 and 43 are advantageously fashioned from a chemically resistant material such as molded or extruded methyl methacrylate resin and are perforated with numerous small holes 52 in order to allow free circulation of the electroplating fluids through the barrel. The holes 52 must be small enough to reject the parts being processed; and in one specific embodiment, holes 52 have been fashioned approximately inch in diameter.

For purposes of rotating the electroplating barrel proper and thereby tumbling the parts charged into it, the drive head 24 is attached to a spur gear 54- which is arranged with its axis coincident with the axis of rotation of the barrel 20. An electric motor 56 or other suitable drive means is supported on a horizontal panel 58 that extends between the standards 26 and 28 above the barrel proper. A pinion gear 60 is mounted on the output shaft 62 of motor 56 to mesh with spur gear 54 applying motive force to the barrel proper.

Turning now to FIG. 5, the ribs 38 and 42 will be seen secured to the head-s 22 and 24 by mounting screws 64 which threadedly engage the ends of the ribs. Advantageously, the heads of the mounting screws 64 are protected from the electroplating solutions by plugs 66 which threadedly engage the sidewalls of counterbores formed in heads 22 and 24. If desired, the plugs 66 may be secured in place using an appropriate adhesive or cement.

Continuing with reference to FIG. 5, the live end fiange assembly or head 22 will be seen to include an inside plate 68 and an outside plate 70 which sandwich therebetween and electrically conductive spider 72, plates 68 and 70 being fashioned from a chemically resistant, electrically insulative material such as polymerized methyl methacrylate resin. The spider 72 is shown in phantom side elevation in FIG. 2; and returning to FIG. 5, the head 22 is shown rotatably mounted to the standard 26 by means of a journal unit indicated generally by the numeral 74, unit 74 being arranged to make electrical connection to the spider 72 while excluding electroplating solutions.

The journal unit 74 includes an elongated bronze bushing 76 which enters a central bore formed in the head 22. A nickel trunnion 78 is fixed to the standard 26 by a flange 80 and screws 82, bushing 76 rotatably receiving the trunnion 78. The trunnion 78 is connected to an electrical lead 84 while the flange 80 is covered with an insulation plate 86 preferably fabricated from polymerized methyl methacrylate resin. Advantageously, a quantity of the resin is polymerized in place about the connection between lead 34 and trunnion 73 to form a resinous plug 88 filling the central aperture in the plate 86.

A sleeve 90, preferably fabricated from a melamine resin-linen laminate is interposed between flange 80 and the bushing 76, sleeve 90 being of approximately the same internal and external diameters as bushing 76. A plate 92 is fixed with respect to the standard 26 surrounding the sleeve 90, and a cooperating plate 94 is fastened to head 22 by means such as the screws 96, plate 94 bearingly engaging the plate 92. A sleeve bearing 98 enters communicating bores in the plates 92 and 94 overlapping the juncture between bushing 76 and sleeve 90, whereas an annular washer element 100 is aflixed to plate 70 in a circular recms formed in plate 94, washer 100 confronting one end of the sleeve bearing 98.

It is to be noted that electrical supply flows from the lead 84 to the trunnion 78 and to the bushing 76. From there, it flows to the spider 72; and it will be observed that the ends of the arms of the spider 72 are coupled to either a contact element 102 or a contact element 104. Each of the contact elements is provided with a neckeddown end 106 which enters a cylindrical bore 108 in the plate 68 to abut the spider 72. Screws 110 threadedly engage the contact elements, drawing the contact elements in place against the spider 72. Desirably, plugs 112 are seated in counterbores over the heads of screws 110 similarly to the use and application of plugs 66 described hereinabove. If desired, additional screw-type fasteners can be used penetrating the ribs radially and engaging the contact elements for additional secural.

. In accordance with an important feature of the invention the contact elements 102 and 104 expose a substantial surface to the parts charged into the barrel 20. Accordingly, the elements 102 and 104 are selected to be relatively massive parts which extend an appreciable distance along the corresponding ribs. With reference to FIG. 5, it will be observed that a contact element 104 extends from the head 22 to within ashort distance d of the head 24. The spacing provided by the distance d permitting suflicient axial shifting of the contact element for disengagingthe necked-down portion 106 from a the bore 108, as would be desired in removing the contact element for cleaning.

The elements 102 and 104 have been fashioned from numerous electrically conductive materials, yellow brass having proved eminently useful in this regard. The elements 102 and 104 also have fashioned in a variety of cross-sectional shapes, a circular or round cross-sectional shape being shown in the several figures.

7 It has proved advantageous to mount the contact elements to the barrel ribs employing an appropriately shaped groove; and as will be seen in FIGS. 3 and 4, grooves 114 have a curved floor for receiving the corresponding contact element in intimate engagement. The longitudinally extending grooves 114 open into the interior of the barrel and, accordingly, are situated between the grooves 50 which receive the side panels of the barrel. It will be noted that the ribs are fashioned with sloping lands 116 between the groove 50 and the groove 114. These lands 116 communicate with the contact elements at an angle approaching the tangential in order to prevent lodging of mechanically aggregated parts in the vicinity of the contact elements. As the barrel rotates during an actual electroplating operation, the small parts charged into the barrel cascade; and the generally pyramidal structure defined by each of the contact elements and its corresponding rib does not form a pocket with the adjacent panels which would tend to collect such parts.

In accordance with a further feature of the invention, the contact elements 102 which are disposed adjacent the removable panel '40 are provided with a longitudinally extending flat surface 118; and with reference to FIG. 2, the planes of the fiat surfaces 118 will be seen to intersect in the general vicinity of the removable panel 40. So arranging the contact elements 102 facilitates discharge of parts from the barrel upon completion of the electroplating operation; and turning to FIGS. 8 and 9, the panel 40 will be seen removed from the gate of the barrel and the majority of the charged parts removed by manually rotating the barrel. A certain portion of the parts collected on the flat surface 118 are shown by the numeral 120. Slight rotation of the barrel in the direction indicated by arrow 122 will dump these parts as is shown in FIG. 9.

With reference to FIGS. 6 and 7, it will be noted that the contact elements 102 and 104 have an inclined surface 124 formed at the free ends thereof. As is shown in FIG. 5, this inclined surface 124 makes an obtuse angle with the unoccupied length of the corresponding rib. This arrangement furthers free movement of the parts during rotation of the barrel in the course of the electroplating operation.

With continued reference to FIG. 5, it will be observed that the ends of spider 72 stop short of the rib mounting screws 64. This advantageous arrangement has proved useful in minimizing the electrical insulation problem and in preventing buildup of plated metal in minute interstices between the several elements of the barrel. The use of rod-type conductive members, such as the contact elements 102 and 104, has been found to permit this arrangement.

Operation of the barrel apparatus 20 will be apparent from the foregoing descriptions.

It is anticipated that electroplating apparatus constructed in accordance with the present invention will find wide fields of utility in the plating of zinc, copper, cadmium, brass and other less expensive metals as well as in the plating of precious metals.

The specific example, herein shown and described should be considered illustrative only. Various changes in structure will, no double, occur to those skilled in the art; and these changes are to be understood as forming a part of this invention insofar as they fall Within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. An electroplating barrel comprising: a pair of barrel heads arranged to be rotated in spaced relationship; a plurality of ribs fixed between said heads at arcuately spaced locations, each of said ribs having a longitudinal, contact member-receiving groove opening into the interior of said barrel and having lands at the opposite lateral edges of said groove; perforated panels between adjacent ribs, including a removable panel; a massive elongated contact member affixed to each of said ribs in the groove thereof, each of said members exposing a substantial area to theparts charged into the barrel, the members adjacent said removable panel being formed with a longitudinally extending fiat surface, the planes of said flat surfaces intersecting in the region of said removable panel and the lands which are adjacent said last mentioned members at the edges thereof away from said removable panel being arranged to define convex surfaces, said convex surfaces cooperating with said flat surfaces to expel small parts from said barrel upon removal of said removable panel and upon rotation of said barrel.

2. An electroplating barrel comprising: a pair of barrel heads arranged to be rotated in spaced relationship. one of said heads being electrically insulative and having an electrically conductive element therein; a plurality of ribs fixed between said heads; perforated panels between adjacent ribs; and a massive contact rod fixed to each of said ribs, each of said rods exposing a substantial area to the parts charged into the barrel, said rods being of lesser length than said ribs whereby to define a free end away from said conductive element, said free end having an inclined surface.

3. An electroplating barrel comprising: a pair of barrel heads arranged to be rotated in spaced relationship, one of said heads being electrically insulative and having an electrically conductive element therein; a plurality of ribs fixed between said heads radially outwardly of said conductive element, each of said ribs having a contactmounting surface facing the interior of said barrel; perforated panels between adjacent ribs disposed radially outwardly of said contact-mounting surface; a contact rod fixed to each of said ribs at the contact-mounting surface thereof in electrical connection with said conductive element, each of said ribs exposing a substantial area to the parts charged into said barrel, said rods being of lesser length than said ribs whereby to define a free end away from said conductive element, said free end having an inclined surface making an obtuse angle with the unoccupied length of said contact-mounting surface.

4. An electroplating barrel comprising: two barrel heads arranged to be rotated in spaced relationship; ribs joining said heads, a plurality of said ribs being each fashioned with a longitudinal, conductive member-re ceiving groove opening into the interior of said barrel, panel-receiving grooves spaced laterally from said conductive member-receiving groove and lands between said conductive member-receiving groove and said panel receiving grooves; fenestrated panels having edges received in the panel-receiving grooves of adjacent ribs; and an elongated conductive member in each of said conductive member-receiving grooves exposing a substantial surface to parts charged into said barrel, said conductive member cooperating wtih the corresponding rib in defining a pyramidal structural between adjacent panels.

5. An electroplating barrel comprising: two barrel heads arranged to be rotated in spaced relationship; ribs joining said heads, a plurality of said ribs being each fashioned with a longitudinal, conductive member-receiving groove opening into the interior of said barrel, panelreceiving grooves spaced laterally from said conductive member-receiving groove and sloping lands between said conductive member-receiving groove and said panel-receiving grooves; fenestrated panels having edges received in the pnael-receiving grooves of adjacent ribs; and an elongated conductive member in each of said conductive member-receiving grooves exposing a substantial surface to parts charged into said barrel, said lands forming wide angles with the juxtaposed panels and with the juxtaposed conductive members whereby to release said parts upon rotation of said barrel.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN ELECTROPLATING BARREL COMPRISING: A PAIR OF BARREL HEADS ARRANGED TO BE ROTATED IN SPACED RELATIONSHIP; A PLURALITY OF RIBS FIXED BETWEEN SAID HEADS AT ARCUATELY SPACED LOCATIONS, EACH OF SAID RIBS HAVING A LONGITUDINAL, CONTACT MEMBER-RECEIVING GROOVE OPENING INTO THE INTERIOR OF SAID BARREL AND HAVING LANDS AT THE OPPOSITE LATERAL EDGES OF SAID GROOVE; PERFORATED PANELS BETWEEN ADJACENT RIBS, INCLUDING A REMOVABLE PANEL; A MASSIVE ELONGATED CONTACT MEMBER AFFIXED TO EACH OF SAID RIBS IN THE GROOVE THEREOF, EACH OF SAID MEMBERS EXPOSING A SUBSTANTIAL AREA TO THE PARTS CHARGED INTO THE BARREL, THE MEMBERS ADJACENT SAID REMOVABLE PANEL BEING FORMED 